Williams, P. H., Thorp, R. W., Richardson, L. L., & Colla, S. R. (2014). Bumble bees of North America: An identification guide. Princeton, New Jersey: Princeton University Press.
Chicago Style CitationWilliams, Paul H., Robbin W. Thorp, Leif L. Richardson, and Sheila R. Colla. Bumble Bees of North America: An Identification Guide. Princeton, New Jersey: Princeton University Press, 2014.
MLA CitationWilliams, Paul H., Robbin W. Thorp, Leif L. Richardson, and Sheila R. Colla. Bumble Bees of North America: An Identification Guide. Princeton, New Jersey: Princeton University Press, 2014.
Warning: These citations may not always be 100% accurate.